Lithographic printing



l R.J.SCHMIDL|N E L 3,521,560

July 21, 1970 LITHOGRAPHIC PRINTING l6 Sheets-Sheet 1 Filed Oct. 20. 1966 mveuroas.

RAYMoNO J. scumom DONALP J. MILLER ATToRNtY.

July 21, 1970, R. .LSCHMIDLIN- ET L 1,560

LI'IHOGRAPHIC PRINTING I Filed Oct. 20, 1966 r r 16 Sheets-Sheet '2 119.13 P-iNK MASTER 3 MASTER cvLmDER NO MASTER 5 FEE-D MASTER I no COPY FEED NO COPY FEED IDL.E STATE- PRE-INKPHASE- PRlr-|T- UT Fi NlSHED (MAINTAIN CYLINDER SEPARATION) CYMNDERS 25 we as saunas a) fl-gJlD ISI :52"

- LAST cow WAS coul vreu PRINT PHASE (CYLmpsR sePARATaoN AND-BIND INK) (ESTABLISH cumoea ENGAGEMENT) iuveu-raas.

RAYMOND .1. scHMmuN D N l-o J. MILL-ER.

y 1970 R. J. SCHMIDLIN ETAL 3,521,560.

' LITHOGRAPHIC PRINTING Filed 001:. 20, 1966 16 Sheets-Sheet 5 Q 380 54 Q I h F FRbM 261' I 2 I PZE1T1 Nq Co FY I 26 c i J INVENTORS. RAYMOND J. SCHMIDLIN DONALD J. MILLER- MOZM ATTORNEY.

Ju y 21, 1970 R. J. SCHMlDLIN ETAL' 3,521,560

LITHOGRAPHIG PRINTING Filed 001'.- 20, 1966 16 Sheets-Sheet 4 'INVENToRs. RAYMOND J. scumouu DONALD J. MILLER ATTORNEY.

Jflly 21, 1970 R. J, scH lD lN ETAL 3,521,560

LITHOGRAPHIC PRINTING Filed Oct. 20, 1966 1e Sheets-Sheet 5 -.|NVENT'0R5. Rim 1 MB J. scmmoun WKM ATTOB N E Y.

DONALD J. MLLLER.

LITHOGRAPHIG PRINTING Filed 001:. 20, 19.66

16 Sheets-Sheet 6 lNVENToRS. RAYMOND J.$cmmm m DOURLD J. MU-LER M 62 AT O KNEY.

July 21, 1970 R. J. SCHMIDLIN ET AL 3,521,560

LITHOGRAPHIG PRINTING Filed Oct. 20. 1966 '16 Sheets-Sheet v INVEN T025. RAYMoNDJ. SCHMIDLIN DONALD J. MILLER.

/imzafxiz ATTORNEY.

July 21, 1970 Filed Oct. 20, 1966 R. J. SCHMIDLIN ET AL LITHOGRAPHIC PRINTING 16 Sheets-Sheet 8 lNVENT'oRs. RAYMOND .J. act-(mount DONAL-D J. MILLER.

ATTORNEY.

July 21, 1970 R. J. SCHMIDLIN ET ,5 1,550

LITHOGRAPHIC PRINTING Filed Oct. 20, 1966 1s Sheets-Sheet 9 a u v "if ourswf. [I26 W 1 j u HI Ill 123;? mvzm'oas.

' RAYMauo-J.scmouoomw J.MILLI'R.

ATTORNEY.

July 21, 1970 R. SCHMIDLI'N E1- AL 3 52 ,560

A LITHOGRAPHIO PRINTING Filed Oct. 20. 1966 16 Sheets-Sheet 10 INVE'MTORS.

RAYMOND J. SCHMIDLIN DONALD J. MILL-ER ATTORNEY.

July 21, 1970 R. J. SCHMIDLIN ETAL 3,521,560

' mrmoemmxc PRINTING Filed 0ct.. 20. 1966 16 Sheets-Sheet 11 l I we FR INVENTORS DONALD J. MILLER.

RAYMOND amscumouz ATTQ KNEY.

July 21, 1970 R. J. SCHMIDLIN ET AL 3,521,560

LITHOGRAPHIC PRINTING Filed Oct. 20, 1966 1e Sheets-Sheet 12 Hln IHII.

mvewroas. RAYMOND J. SCHMIDLIN DONALD J. MILLER ATTORNEY.

July 21, 1970 Fild Oct. 20, 1966 R. J. SCHMIDLIN ET AL LITHOGRAPHIC PRINTING l6 Sheets-Sheet 15 W "Hil A ll mmw'

. lNvE'm'r'oias.

RAYMOND .J. SCHMIDLIN DONALD J. MILLER.

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y 1970 R. J, SCHMEDLIN ET AL 3,521,560

LITHOGRAPHIG PRINTING Filed Oct. 20, 1966 1e Sheets-Sheet 14 INVENTOIZS.

RAYM ND JSCHMIOLIN DONALD J. MILLER.

WKAZ ATTO RNE Y.

July 21, 1970 R. J, sc lDLl ET AL 3,521,560

LITHOGRAPHIC PRINTING l6 Sheets-Sheet 15 Filed Oct 20, 1966 MIR INVENTORS. 4i RAYMOND J. SCHMIDLIN 1 I J85 oouaw .J. MILLER BYMOK I WATTORNEY. H

US. Cl. 101-145 21 Claims ABSTRACT OF THE DISCLOSURE A lithographic duplicator embodies a two cylinder printing arrangement with the master cylinder and a directly contacting impression cylinder so disposed that their common axial plane is situated at an angle to the vertical. Masters are fed generally horizontally and tangentially to the bottom of the master cylinder and are ejected at the top. Copy sheets are fed generally horizontally and tangentially to the bottom of the impression cylinder at a position somewhat less than 180 away from the printing line, and are fed away at the top, just after passing the printing line. The mechanism for separating the cylinders in case a copy sheet fails to feed embodies a delay mechanism to permit completion of printing of the previous copy sheet after misfeed is detected for a time long enough to enable the previous copy sheet to clear the printing line. Automatic controls are provided, including especially means for predetermining the number of times the master is inked before copy sheet feeding is started, and means for withdrawing the moistening fluid from the fountain except during a duplicating run.

This invention relates to lithographic printing machines and in particular to printing wherein an image is offset directly from a master onto a copy sheet or an impression cylinder without the intervention of the conventional blanket cylinder.

The more conventional lithographic printing machine is characterized by an arrangement which includes three cylinders. First there is the rigid master cylinder on which is supported the master bearing the image to be duplicated; secondly, a blanket cylinder supporting a relatively soft and resilient blanket of rubber or equivalent material in tangential contact with the master to receive an image therefrom; and third, an impression cylinder presenting an effective printing couple by tangential engagement with the blanket, the sheet to be printed being passed into the bight between the blanket and the impression cylinders.

Further in connection with the principles of printing involved in the present invention, it is generally recognized that a lithographic duplicator is among the best, if not the best, in quality of printing produced, with relation to so-called oflice duplicators. This is so for the reason that the master sheet itself is prepared under high quality circumstances presenting a sharp and precise image. The way in which the master sheet is prepared and processed makes it possible to prepare duplicates or prints therefrom that are virtually of the quality of the original image presented by the master and in fact good half-tone photographic work can be easily realized.

These characteristics of lithographic printing depend for the most part on the basic oleophilic-hydrophilic balance. The oleophilic response of the master makes it possible to delineate thereon a strong image compatible with a high quality greasy or oil-base lithographers ink, while at the same time the unimaged or background portions of the master are hydrophilic in nature so that by applying moisture to the master, the inherent oleophobic nature of the water will confine the ink precisely to the -United States Patent 3,521,560 Patented July 21, 1970 original or master image. Consequently, the image transferred or offset from the master to the copy sheet is sharply defined, more so than in any other oflice-ty-pe duplicator.

Although there is no question as to the advantages from the standpoint of quality printing presented by the use of the blanket cylinder, nevertheless the intervention of the blanket cylinder interposes factors of time and expense in maintenance which conceivably could be obviated if a direct lithographic printing machine could be constructed without substantial sacrifice or compromise in the high quality printing ordinarily accomplished through the intervention of a blanket cylinder. This observation would be especially applicable in the instance of office duplicators where high rates of production of copies of superior quality could be obtained, superior to the copies available with duplicators operating on nonlithographic principles.

Accordingly, it is the primary object of the present invention to attain a high rate of production of copies in a printing machine operating on the lithographic principle and capable of installation for office work, and related object of the present invention is to enable such high rate of production to be accomplished by so constructing a master cylinder and a directly contacting impression cylinder as to produce excellent quality prints, such as are ordinarily obtained in a lithographic printing machine utilizing a blanket cylinder interposed between the master cylinder and platen or so-called impression cylinder.

Thus, the machine of the present invention is characterized by a master cylinder and an impression cylinder so arranged as to present the basic printing couple wherein a copy sheet on the impression cylinder will be brought into direct tangential contact with the imaged master presented by the master cylinder.

A high rate of production is achieved under the present invention at minimum cost and maintenance not only because of a successful elimination of the blanket cylinder, but also because of the unusual way in which the operating units of the machine are arranged in such a fashion as to enable the master as well as the copy sheets to be advanced to and stripped from the machine while taking advantage of the rotary paths that are inherent in the master and impression cylinders, and so to do constitutes another of the more important objects of the present invention. More specifically in this regard, it is a further object of the present invention to create a space advantage by aligning the axes of the master cylinder and impression cylinder on a plane that is displaced from a vertical reference plane extended from the line of printing contact between these cylinders, and by so doing it is found that the usual automatic clamps can be more effectively operated to clamp the master to the master cylinder and the successive copy sheets to the impression cylinder. In other words, under this object of the present invention, automatic insertion and ejection of the master as well as the copy sheets can be paced to comply with an optimum rate of operation of the feed means for the copy sheets, and this is so for the reason that the creation of the space advantage mentioned above really presents a tolerance in time for operating automatic clamps on the master cylinder. In other words, by displacing the cylinder axes as noted above, it is found that automatic clamps for the master and the copy sheets, on their respective cylinders, can be operated at a speed which keeps pace with the desired high rate of feed of copy sheets.

A further object of the present invention is to utilize the same space advantage to accommodate the most desirable form of feeding moisture to a lithographic master, which is recognized as manifest in an ascending train of 3 moistening rollers. Thus, an ascending train of moistening rollers assures that there will not be an excessive amount of moisture fed to the imaged master, so that another object of the present invention is to enable this principle to be utilized while realizing the high rate of production noted above.

A further object of the present invention is to enable high speed operation to be achieved, manifest in the advancement to the impression cylinder of a new copy sheet to be printed at a time when the previous copy Sheet is on the impression cylinder undergoing printing, and from this it will be seen that in accordance with this aspect of the present invention, the second copy sheet will in effect be in ready position for printing at a time when the previous sheet is still in the process of being printed.

In this connection, it should be noted that it is customary that the machine be so arranged as to assure that the master cylinder and impression cylinder will not be effectively coupled to produce a print in the event there is failure to feed a demanded copy sheet. This would normally be accomplished by enabling the impression cylinder to partake of cyclic movement in the normal course of a machine cycle between a first position, where the impression cylinder is spaced from the master cylinder (ineffective to produce a print) and a second position where the two cylinders are effectively coupled to produce a print; and further by providing means to hold and maintain the second position so long as there is a succession of demanded copy sheets advanced to the impression cylinder. If there is failure to feed a demanded copy sheet, then means are operable to assure the first position for the impression cylinder thereby avoiding contact between the imaged master and the impression cylinder. It will be appreciated of course that it would be undesirable, and in fact would interfere with good copy Work, to transfer an image to the impression cylinder when there is no copy sheet on the impression cylinder. A further object of the present invention, then, is to make provision for sensing or detecting the presence of a copy sheet at the threshold or ready position and simultaneously to store or register information either as to the positive or negative circumstance of a copy sheet at the ready position. This object of the present invention is consistent with the desire for high speed operation, characterized by the simultaneous occurrence of a sheet undergoing printing and a new sheet adjacent the impression cylinder awaiting the next printing cycle. As a result, actuation of the registering means for the positive circumstance of an awaiting copy sheet enables this information to be acted upon simultaneously with the event of a'copy sheet undergoing printing, and thus it will be seen that a significant object is realized in that the machine is so arranged as to enable both a current and a future event to be simultaneously handled by the machine. Further in this regard, the parts are so arranged insofar as concerns sensing, registering and concurrent printing, as to enable the master cylinder and impression cylinder to prepare for the printing of the next copy at the time the current copy is undergoing printing; and in the event that there is failure to feed a demand copy sheet the parts are so arranged as to assure that in the subsequent machine cycle, when a print would ordinarily be effected, the impression cylinder will be shifted to its first or non-print position even though, at the time when the failure to feed is detected, the current copy is still undergoing a printing operation which must be completed before the cylinders can be separated.

High quality prints in accordance with the present invention are attained by initially subjecting the master to a pre-ink phase of operation, withholding the first of the copy sheets until after there has been a good build-up of ink on the imaged master for the duplication work in the next or print phase of operation. Accordingly, and as a further object of the present invention, means are provided to maintain the impression cylinder and master cylinder separated in the non-print position until a form roller in the ink system has been effective to apply ink to the imaged master for a predetermined number of revolutions of the master cylinder, and thereafter this means is disabled as an incident to establishing conditions for advancing the first of a predetermined number of copy sheets successively through the machine. Thus, the present machine is so constructed as to enable the inked image on the master to be adequately prepared for superior copy work, and a corollary thereto is to separate the form roller from the master and to disengage the master cylinder and the impression cylinder following the event of the last of the demanded copy sheets.

It will be appreciated from the foregoing discussion that the machine of the present invention can be set to print a predetermined number of sheets, and a counter is provided for this purpose. When the counter indicates that the last of the copy sheets has indeed been advanced to the ready position, conditions are established for producing the aforesaid cylinder separations at the appropriate time following completion of printing of the last copy sheet.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show a preferred embodiment of the present invention and the principles thereof and what is now considered to be the best mode contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention.

In the drawings:

FIG. 1 is a perspective view of a machine constructed in accordance with the present invention and wherein covers for the machine are shown as removed to expose operating parts of the machine;

FIGS. 1A through 1D are diagrammatic views illustrating different phases of operation of the machine;

FIG. 1B is a sectional view of the machine, partly schematic and illustrating the manner in which operating elements of the machine are in a quadrant relationship;

FIG. 2 is a partial side elevation of the machine;

FIG. 3 is a fragmentary sectional view of the machine;

FIG. 4 is another side elevational view of a portion of the machine on an enlarged scale in comparison to FIG. 2;

FIG. 5 is an elevation similar to FIG. 4, but on an enlarged scale and showing the parts in different position;

FIGS. 5A, 5B and 5C are detail schematic views illustrating the operation of certain cams and parts related thereto;

FIG. 6 is a view similar to FIG. 5, but showing the parts in a different phase of operation;

FIG. 7 is a side elevational detail view substantially on the line 77 of FIG. 8 showing operating parts related to control of the form roller;

FIG. 8 is a plan top view substantially on the line 88 of FIG. 7;

FIG. 9 is a bottom plan view substantially on the line 99 of FIG. 7;

FIG. 10 is a view similar to FIG. 2; and at the opposite side of the machine;

FIG. 11 is a view similar to the upper portion of FIG. 10 showing parts associated with the form roller and ink ing system to a larger scale;

FIG. 12 is a fragmentary detail sectional view of the. machine showing the form roller mounting;

FIG. 13 is a detail sectional view illustrating the copy Sheet sensing means taken substantially on line 1313. of FIG, 5B;

FIG. 14 is a perspective end view on an enlarged scale, substantially on the line 1414 of FIG. 1;

FIG. 15 is a detail view, partly in section, of certain parts associated with means for feeding the copy sheets;

FIG. 16 is an elevational detail view showing parts of the machine related to pre-treatment and feeding of the master;

FIGS. 16A and 16B are section taken respectively on the lines 16A16A and 16B--16B of FIG. 16;

FIG. 17 is a sectional view of the ink and moisture system associated with the form roller and master cylinder;

FFIG. 18 is a detail perspective view, with certain parts exploded, showing the master clamp means and parts associated therewith;

FIGS. 18A and 18B are detail elevations showing features of master insertion and ejection; and

FIG. 19 is a wiring diagram.

PRELIMINARY DESCRIPTION Theduplicating machine of the present invention operates on the principle of lithography utilizing a paper base master, but a lithographic master of other suitable form may be used, since the basic requirement is a flexible sheet bearing a reverse reading image of such character that the image will accept ink while rejecting water, whereas the unimaged, background portions of the sheet will accept water but reject ink. Consequently, ink applied to the master will be restricted to the image portions and can be offset or transferred image-wise in direct reading fashion onto a copy sheet.

Referring to FIGS. 1A through 1D, these views illustrate schematically certain sequences of operation of the duplicating machine of the present invention identified as 20 in FIG. 1. Thus, the machine 20 includes a master cylinder 25, FIG. 1A, to which the aforesaid master will be clamped, and therebelow is an impression cylinder 26 to which will be clamped the copy sheet to receive an offset image from the master on the master cylinder. In the idle state of the machine, as shown in FIG. 1A, the master cylinder and impression cylinder 26 are separated to be out of contact with one another, and a form roller 30 is, at this time, out of contact with the maser cylinder. It should be noted that the form roller is effective, when in operative position, to apply ink and moisture to the master that is clamped on the master cylinder, the form roller being one of a series.

In the pre-ink phase of operation, as shown in FIG. 1B, the master has been clamped to the master cylinder,

and the form roller has been lowered into contact with the master to apply ink and moisture thereto for a predetermined number of revolutions of the master cylinder, there by conditioning the master for ultimate effective transfer of an ink image to each of the copy sheets to be printed. At this time, however, the impression cylinder is still separated from the master cylinder to restrict the application of ink to the master alone, and no copy sheet is fed to the cylinder 26.

Following the pre-ink phase of operation, and as an incident to a count-down determination that the required number of pre-inking cycles has been satisfied, the first sheet to be copied is advanced to and clamped on the impression cylinder, FIG. 1C, and concurrently in the machine cycle the impression cylinder is elevated to bring the sheet to be copied into printing contact with the master on the master cylinder. An image is offset from the master sheet to the copy sheet, the printed copy is ejected from the impression cylinder, and a new copy is advanced to the impression cylinder during the print phase as shown in FIG. 1C. The form roller continues to apply ink moisture to the master, the latter being retained in engagement with the master cylinder until the required number of copies have been printed.

The machine includes a sensing device effective to detect the passage of a copy sheet to the impression cylinder. Actuation of this sensing device is a signal for a sequence of events which will result in cylinder engagement. If there is failure to feed a demanded copy sheet, cylinders 25 and 26 will be separated. The copy sheets thus detected are counted, and upon satisfaction of the required number of copies, FIG. 1D, the master is ejected from the master cylinder, the form roller 30 is elevated to its inoperative position and the cylinders are again separated to comply with the circumstance illustrated in FIG. 1A. There is no attempt in FIGS. 1A through 1D to illustrate the precise timing of these occurrences.

Referring to FIG. 1B, an important feature of the machine of the present invention is manifest in the axes of the master and impression cylinders themselves being contained in an operating plane or axis 0A inclined at a substantial angle relative to a vertical reference line VRL. This arrangement contributes to enhance operation as will be explained in more detail below; and a further factor contributing to enhanced operation, particularly from the standpoint of speed and the feeding of moisture to the form roller, is the manner in which certain operating units of the machine are assigned to the quadrants I, II, III and IV defined by the intersection of the reference line VRL with a horizontal reference line HRL.

It was mentioned in the discussion above that the machine of the present invention is capable of high quality work in spite of the fact that the ordinary blanket cylinder is eliminated. This is made possible by surfacing the master cylinder with a sheet of rubber 25R, FIG. 1E, secured in any desired fashion, as by clamps or the like, to the underlying, rigid supporting surface of the master cylinder. At the same time the surface of the impression cylinder presents a rigid and non-compliant surface 26C, preferably presented by a layer of chromium for reasons explained below.

By so defining the surfaces of the master cylinder and impression cylinder, a resilient support for the image to be transferred to the copy sheet is achieved, while at the same time the chromium surface on the impression cylinder presents a strongly hydrophilic, oleophobic, ink-rejecting surface. Thus, the rubber sheet 25R on the master cylinder, which will underlie the imaged master when the latter is clamped thereto, enables the master to be conformant or compliant in the course of pressure contact with the copy sheet on the impression cylinder, and in this fashion a soft or yielding printing contact, characteristic of a blanket cylinder, is achieved. At the same time, the chromium surface, presented by the impression cylinder, will reject the slight vestige of background ink which might tend to be offset onto the portions of the impression cylinder that outline the borders of the copy sheet, and accordingly, despite extended operation without cleaning, assurance is had that the surface of the impression cylinder supporting the copy sheet will not accumulate any marginal ink deposits tending to smudge copy sheet edges or impair machine operation.

In the actual machine, copy sheets CS, FIG. 1, are maintained in a supply stack at the left-hand side of the machine, as viewed in FIG. 1, in position to be advanced forwardly one-by-one by copy sheet feed means in the direction of the impression cylinder 26, FIG. 4. The master sheet bearing the image to be duplicated is advanced from the right-hand side of the machine, as viewed in FIG.'4, toward the master cylinder 25, and is forced up against a stop finger 31, FIG. 4, serving a function to be explained hereinafter.

The main drive for the machine is supplied by a motor M, FIGS. 3 and 4, effective to drive a belt B, FIG. 4, in turn connected to a main drive pulley 33, FIG. 3. The pulley 33 in turn is effective to rotate a main drive shaft 34 to which is connected a related gear train 35 responsible for imparting rotation to the impression cylinder and the master cylinder as well as the various driven parts related thereto. Inasmuch as the exact drive connections constitute no part of the present invention, a further description thereof is not necessary.

PRE-INK PHASE OF OPERATION AND THE ES- TABLISHMENT OF CONDITIONS FOR EFFECT- ING FEED OF THE COPY SHEETS As noted above, the impression cylinder is normally separated from the master cylinder. No copy sheet will be fed to the impression cylinder until after the master has been clamped to the master cylinder, and the image thereon pre-inked to build up the ink image to the desired extent by engaging the form roller with the master sheet on the master cylinder 25. Normally, the form roller is separated or spaced from the master cylinder, which is to say that the form roller is not lowered to operative position until after means have been effective to determine that a master sheet has in fact been advanced to and clamped on the master. This is explained in more detail below.

The master sheet is prepared at a separate station as hereinafter explained, and from this station is advanced by delivery rollers (as will be explained below) so that the leading edge thereof will bear against the stop finger 31, FIG. 4. The leading portion of the master sheet is in position between a pair of feed rollers and 41 which at this time are separated. The master sheet is buckled due to the forcing action of the aforesaid delivery rollers, and in such buckled condition, the master sheet is effective to elevate a sensing finger 44, FIG. 4, which closes a master sheet detector or so-called master arrival switch 45 indicating that the master is in ready position. Until this switch is closed as an incident to buckling of the forwardly fed master, the machin will continue to idle.

Upon closure of the switch 45 as an incident to sensing the presence of the master sheet in position to be advanced to the master cylinder, a master insertion solenoid 290, FIG. 4, is energized, as well as a feed roll sole-.

noid, 46R, FIG. 10. When this occurs the feed rollers 40 and 41 engage the master sheet and the stop finger 31 is retracted in a manner hereinafter explained, allowing the master to be fed forwardly by the rollers 40 and 41 inposition to have the leading edge thereof clamped to the master cylinder, providing the previous master sheet has been released from the cylinder 25, as will be explained.

The clamping structure for fastening a master to the master cylinder 25 and the means effective for stripping a used master from the cylinder 25, including the stripper blade 50, FIG. 4, and a pair of ejector rollers 51, will be described in more detail below.

When any previous master is released from the cylinder 25 and the current master has been clamped thereto, a form roll solenoid 52, FIGS. 10 and 11, is energized. This results in the form roller 30 being lowered to apply ink and moisture to the master which is clamped to the master cylinder 25. Means are provided to count out a predetermined number of pre-ink cycles or revolutions of cylinder 25, and when such count is completed an ink switch 54, FIG. 7, is closed. This conditions for operation the means effective to advance the copy sheets to be clamped to the impression cylinder.

The form roller 30, FIG. 12, is disposed between the side plates 57 and 58 of the machine, and is carried in a form roller support bracket 60, FIGS. 11 and 12, for oscillation between its inoperative and operative position. Such oscillation of the form roller occurs about the pivotal axis 60A of the bracket 60, and in FIGS. 11 and 12 the axis of rotation of the form roller 30 is identified by the reference character 38A. A spring 61, FIGS. 10 and 11, is normally effective to urge the support bracket 60 in a counterclockwise direction as viewed in FIG. 10, which would correspond to the form roller being urged into contact with the master on the master cylinder 25. However, this action is normally prevented by a cam 64, FIG. 10, which prevents a holding lobe to a projecting finger on the form roller support bracket 60, whereby the cam 64 is effective to maintain the form roller 30 in an elevated position separated from the master cylinder. As stated, this normal position is indicated in FIG. 10, but in FIG. 11 there is shown the circumstance where the cam 64 has been shifted to permit the form roller to engage the master cylinder. Positioning of the cam 64 in the attitude shown in FIG. 11 is accomplished in the following manner.

The armature 52A, FIG. 11, of the form roller solenoid 52 depends therefrom in a vertical position and is connected to a slide cam 68 supported at the side of the machine as shown in FIG. 10. This slide cam is guided for vertical movement by a pair of guide pins as 68P em braced by a guide slot 68S in the cam 68. Normally the slide cam 68 is urged to a lower position by a spring 70 connected at one end to the lower portion of the slide 68 and anchored at the other end to a pin projecting from the corresponding side plate of the machine.

Positioning of the form roller control cam 68 is under control of a ratchet drive bar 73 and a release or back-up bar 74, FIG. 11. These bars are disposed in a horizontal attitude at the side of the machine, as will be apparent from FIG. 10, and are arranged for reciprocal motion along horizontal paths. The left-hand end of each bar 73 and 74 as viewed in FIG. 11 normally bears against a related stop pin 73A and 74A respectively. The opposite ends of the ratcheting bar and the release back-up bar are adapted to bear against respective pins 64A and 64B on the cam 64. The cam 64 is free to turn about an axis 64P.

Bars 73 and 74 are supported and guided for horizontal motion in a pair of vertically disposed guide bars 76 and 77, FIG. 11, having the rear faces thereof notched to receive the bars 73 and 74. Springs 78 and 79 are normally effective between the pins 68P and pins 80, fastened to the bars 73 and 74, to urge the latter leftward as viewed in FIG. 11 so that the lefthand ends of the bars 73 and 74 bear against the related stops 73A and 74A.

A pair of spring-biased pawls 83 and 84, FIG. 11, are related respectively to the bars 73 and 74. These pawls are pivotally supported, as shown in FIG. 11, at the opposite upper and lower ends of a vertically disposed support bar 85. The opposite end of each pawl 83 and 84 is provided with a pawl finger 83F and 84F adapted to engage a related notch 73N in the bar 73 and notch 74N in the bar 74. The pawls tend to be urged to a notch engaging position by respective springs 87 and 88.

The pawl support is secured to a pawl carrier bar 90 disposed in a horizontal attitude between the bars 73 and 74 as shown in FIG. 11, and is guided for horizontal movement in the same fashion as the bars 73 and 74. Consequently, any horizontal motion of the carrier bar 90 is accompanied by lateral motion of the pawls 83- and 84 in the same direction. The carrier bar 90 is driven by a vertically disposed pawl drive arm 92, there being a pin 90P on the pawl carrier bar 90 disposed within a slot 93 in the arm 92 establishing the required drive connection. The arm 92 is adapted to oscillate about an axis 92A. The arm 92 is provided with a cam follower 94, FIG. 10, and this follower is adapted to be engaged by a cam 95, FIG. 10, which cooperates with a return spring 96 in effecting oscillation of the arm 92 about the axis 92A. Thus, the spring 96 is anchored at one end of a pin 92F on arm 92 and at the other to a pin 97 projecting from the side plate of the machine. On the other hand, when the cam is effective to produce clockwise motion of the arm 92, such motion is accompanied by lateral movement of the pawl driver 90 in a right-hand direction as viewed in FIG. 10'. Cam 95 rotates in timed relation to the master cylinder 25.

Until the solenoid 52 is energized, the parts are in the disposition shown in FIG. 10, and under such circumstances the cam slide 68 is urged downwardly by the spring 70 so that the lower cam edge 68L thereof 

